Apparatus for enlarging and reducing transfers



(No Model.)

P. WpMcDONALD. APPARATUS FOR BNLARGING AND REDUCING TRANSFERS. No. 269,220.- v Patented Dec. 19, 1882.

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NITED STATES PATE T FFICE.

PETER W. MCDONALD, OF CLEVELAND, OHIO.

SPECIFICATION forming part of Letters Patent No. 269,220, dated December 19, 1882.

Application filed February 10, 1882. (No model.)

To all whom it may concern:

Be it known that I, PETER W. MCDONALD, of Cleveland, in the county of Onyahoga and State of Ohio, have invented a new and useful Apparatus for Enlarging and Reducing Lithographic Transfers, of which the following is a specification.

This invention relates to an apparatus for transferring designs or drawings to lithographic stones, as hereinafter described and claimed.

In the accompanying drawings, Figure l is a perspective view of the above-mentioned apparatus. Fig. 2 is a detached view of the gear at the corner of the main frame for operating the expanding-screws, (enlarged) Fig. 3 is an enlarged detached view of one of the cornerblocks of the expanding frame, showing manner of attaching the elastic sheet to said frame.

A is a frame,which supports all of the working parts. It is provided with legs at thefour corners for supporting it over a stone while operating the apparatus. In the inside of said frame A are arranged four long right and left handed screw-threaded rods, B B, journaled in suitable boxes near the corners. These screwrods are made to revolve in concert by means of gear with pulleys and chain-belts arranged in the outside of said frame A. The screw-rods B pass through the rails of the frame A to connect. One of rods Bis provided with gear and sprocket wheel (3 and a hand-crank, c. The gear (3 meshes with a similar gear set in a bracket, b. on the corner of the frame. The shaft of this gear carries a bevel-pinion, d, which operates a bevel-gear, D, on the screwrod at the right side of the frame. Sprocket wheel 0 is connected to a similar wheel, E, on the end of screw-rod, at the farther side of the frame, by a chain-bolt, F. Bevel-gear D also has a toothed periphery, and is connected to a sprocket-wheel on end of screw-rod at left side of the frame. By this means the crank operates allthe screws alike and all at the same time. Upon each of the saidrods B are two traversing nuts, G, having arms g, with slots or sockets,in which the ends of the rods of the expanding frame rest.

The expanding frame consists of fourrods, H, having a button on each end to hold the rods in the slots ofthe arms 9. The rods H are passed through blocks I, in which they slide when in the act of stretching or contracting the said frame. Upon each of the rods H, be-

tween and attached to the said sliding blocks I, is placed an elastic or rubber sleeve, J, in which is secured the elastic transferring-sheet K by means of small staples and pins is, put through eyelets in said sleeve and sheet, as seen in Fig.3. This sleeve holds the sheet securely throughout its length along the edges, and perfectly stretches the sheet as well along the edges as the central or other portions. The sliding blocks I are provided with vertical thumb-screws L for the purpose of binding the corners of the frame together, when desired to remove the same from the main frame. The blocks I are also provided with vertical screws M, which are for the purpose of adjusting the frame to the surface of a stone, and for the purpose of raising it from the stone when it has received or given an impression.

The elastic sheet K is made of india-rubber, and for the purpose of making it susceptible of receiving impressions I coat the transferring surface with a thin coat of a mixture of glycerine and dextrine, which makes it sufficiently sticky to take up and retain the ink from an engraved stone or plate, and give off the ink when applied to a fresh or clean stone.

From the foregoing the operation of this apparatus is seen to be as follows: For reducing and transferring a design, the elastic sheet, being previously prepared to receive the impression, is first expanded or stretched to the required limit by turning the crank c, which operates the screw-rods B, carrying the traversing nuts'Gr outward, thus drawing the rods H with them and enlarging the elastic sheet, which then may be pressed down upon a stone and receive the ink-impression. The sheet is thus carefully raised from the stone by turning the screws M until it is free, then removing the whole apparatus from over the stone. The sheet is again contracted by turning the crank back until the sheet has resumed its normal size. Now, the apparatus may be set over another stone, and the transfer made by suitable means. Thus the design is transferred, is reduced in size and in exact proportion, and is ready for printing. For enlarging, a reverse operation is required.

Having described my invention, I claim as follows:

An apparatus for expanding an elastic sheet for transfer purposes, consisting of frame A, theelastic sheet K, constructed, combined, and right and left hand screw-threaded rods B B, operating substantially as and for the purpose gears O D d, sprocket-wheels O D E, chainspecified.

belts F, traversing nuts Gr, having slotted arms PETER W. MGDON ALD. g, expanding frame H, with blocks I, having Vitnesses:

vertical screws L M and the flexible sleeves J Gno. W. TIBBITTS,

provided with staples and pins 70 for securing E. V. LAIRD. 

